Algorithms for estimating traffic density and for traffic-jam warning or for detecting disruptions in road traffic are already known. These algorithms process static and/or dynamic traffic data, which are obtained via measuring loops embedded in the roadway or by measurements in individual vehicles. In individual vehicles, distance data for preceding or subsequent vehicles are ascertained with the aid of measurement devices of an intelligent cruise control or of a so-called ACC system (ACC=adaptive cruise control), or the velocity of the vehicle is recorded, etc. Such algorithms for evaluating the traffic situation are normally used in traffic control centers, but may also be used directly in the on-board computer of a vehicle for processing these data. In this connection, the vehicle-vehicle communication, which is presently being developed, allows for the exchange of data that are necessary for such calculations.
In addition to such central systems for detecting the traffic situation, vehicle navigation systems are described, for example, in U.S. Pat. No. 5,291,412, that can determine the current position of the vehicle with high accuracy, as a rule using satellite support. Current vehicle navigation systems calculate the shortest, quickest or “optimal” (as a rule, a mixture of these two criteria) route from the current vehicle position to the desired destination. In this context, current traffic messages are taken into account so that systems having a corresponding TMC connection may avoid traffic jams when the alternate route is more favorable.
Moreover, design approaches are known that are called so-called lane assistants, which monitor the lane behavior of a vehicle with the aid of sensors and inform the driver if the vehicle leaves a lane on which it has been traveling. In this way, the vehicle is prevented from unintentionally deviating from the lane.
However, to date the known systems are used only for route guidance or traffic control, but not to evaluate the safety of planned driving maneuvers. The topic of safety is playing an increasingly important role in vehicle concepts. The point is no longer only to be guided as quickly as possible to the destination, but rather also to be guided as safely as possible. At the moment, this is ensured by providing driving instructions early. However, in the event of unfavorable traffic conditions, the driver may not be able to follow the instructions, for example, to exit an expressway, in time, perhaps because he is located in the outermost passing lane and the other lanes, which he would have to cross, are relatively crowded. Following the driving instruction would possibly mean putting the driver and the other road users in danger. To date, it is not possible for the vehicle navigation system to detect such a dangerous situation. Thus, it would be desirable to expand the known systems in this regard.